I needed a tool to alert me when my cron jobs silently fail. There is already a number of existing services for this, but it seemed like a fun thing to build myself. So I present to you: healthchecks.io. I am using this myself and it has already been useful for me a couple times. Say, a seemingly benign code change in one service causes my batch job to fail 12 hours later, in the middle of night.
Understand.io is an online event and log management system which enables you to release immense value from log data that you already collect. You can get complete application visibility in real-time, helping you to track down error messages, application requests, customer problems, and much more.